The present disclosure relates to an optical information recording reproduction apparatus and an optical information recording reproduction method capable of recording and reproducing information by emitting a beam to a medium.
There has been suggested an optical recording method of performing volume recording of information by condensing a high-power laser beam on an optical information recording medium with a bulk shape and transforming the material of a recording layer near a focus (for example, see Seiji Kobayashi, Kimihiro Saito, Takashi Iwamura, Hisayuki Yamatsu, Toshihiro Horigome, Mitsuaki Oyamada, Kunihiko Hayashi, Daisuke Ueda, Norihiro Tanabe and Hirotaka Miyamoto, Tech. Digest of ISOM'09, Th-I-01 (2009)). According to this method, it is possible to perform the volume recording using an inexpensive cheap medium and realize low cost and large-capacity optical recording.
In the optical recording method, it is particularly preferable that a recording medium has a two-photon absorption property. Since the two-photon absorption property is shown only in a region where an optical power density is extremely high, a recording beam is absorbed only in the vicinity of the focus. Therefore, the other regions of the recording medium are not subjected to the attenuation. Accordingly, since the recording beam can arbitrarily reach any depth position in the recording medium, the volume recording can efficiently be performed.
In the optical recording, it is considered that voids (vacant holes) are formed in a thermal manner or an ablation manner by the energy of the beam two-photon absorbed near the focus of the beam condensed to the medium (for example, see Eugene G. Gamaly, Saulius Juodkazis, Koichi Nishimura, and Hiroaki Misawa, Phys. Rev. B 73, 214101 (2006)).
Besides a case where an infrared pulse laser is used in recording, it has been reported that two-photon absorption recording is realized by an infrared CW laser (for example, see Min Gu and Daniel Day, Opt. Letters, 24, 5 (1999)).